Reactions Faster than Actions, Study Finds

The mythology of the Wild West suggests the person who draws first
in a gunfight is usually the first to get shot, and new findings now
hint at a reason why this might happen.

Inspired by Hollywood cowboy movies, Nobel Laureate atomic physicist
Niels Bohr once conjectured why, during a duel, the gunslinger who drew
first was the one to get shot — the intentional act of drawing and
shooting is slower to carry out than the "quick draw" response to
another gun. Anecdotal reports note that Bohr tested his idea using toy
pistols, with the reactive Bohr apparently winning every duel against
his colleague George Gamow.

Now an international team of scientists has found a basis for this idea — people move faster when reacting than when initiating the same movement. But the ultimate outcome is not so simple.

Shootout at the O.K. Lab

In laboratory versions of gunfights,
the researchers had volunteers each press a row of three buttons. When
they faced off against other "gunslingers" — either people directly
across from them, people in another room, or computers — the volunteers
on average were roughly 10 percent faster when they reacted than when
they initiated "shootouts," a boost in speed of roughly 21 milliseconds
they dubbed "the reactive advantage."

Still, while participants moved faster when reacting than
initiating, reactors only rarely beat initiators. The extra
milliseconds it took volunteers to respond to the movements of their
opponents greatly offset any benefit the reactive advantage granted.

"As a general strategy for survival,
having this system in our brains that gives us quick-and-dirty
responses to the environment seems pretty useful," said researcher
Andrew Welchman, an experimental psychologist at University of
Birmingham in Britain. "Twenty-one milliseconds may seem like a tiny
difference, and it probably wouldn't save you in a Wild West duel
because your brain takes around 200 milliseconds to respond to what
your opponent is doing, but it could mean the difference between life
and death when you are trying to avoid an oncoming bus!"

These findings also suggest that Bohr's victories in his duels could
not be ascribed to the reactive advantage. Instead, "he was probably
just a very good shot," Welchman said.

What's going on?

The researchers now want to learn what is responsible for this
difference between intentional and reactive actions. They suggest the
brain circuits that control reactive actions could be faster than ones
in charge of intentional motions, providing a potentially useful means
of promoting survival.

"One idea is that when we are reacting to the things around us in
the world, that information comes in from the eyes, gets sent to the
back of the brain,
and then from the back of the brain up towards the areas that control
our movements," Welchman explained. In contrast, when one makes an
intentional action, the information goes from the decision areas in the
front of the brain back toward the motor areas in charge of movement.

"The key idea is that effectively, the brakes get taken off faster
when we are making reactive movements so we can get moving faster than
when we're making intentional movements," he said. "That could be
responsible for us being 20 milliseconds quicker when we respond to our
opponents." However, what one gains in speed might be lost in accuracy,
the researchers added.

There might be some evidence for two different brain systems in
people with Parkinson's disease — for instance, they might find it far
harder to pick up a ball from a table than they would to catch the same
ball if it were thrown at them. If Parkinson's does indeed affect areas
of the brain that contribute more to intentional actions than reactive
ones, it might be possible to develop strategies to ease movement in
such patients, the researchers added.

The findings will be detailed online Feb. 3 in the Proceedings of the Royal Society B: Biological Sciences.

Charles Q. Choi

Charles Q. Choi is a contributing writer for Live Science and Space.com. He covers all things human origins and astronomy as well as physics, animals and general science topics. Charles has a Master of Arts degree from the University of Missouri-Columbia, School of Journalism and a Bachelor of Arts degree from the University of South Florida. Charles has visited every continent on Earth, drinking rancid yak butter tea in Lhasa, snorkeling with sea lions in the Galapagos and even climbing an iceberg in Antarctica.